A wild giant panda may roam the bamboo groves of China all day eating 25 species of bamboo, but not a zoo panda. The San Diego Zoo’s Horticulture Department grows bamboo for the giant pandas in the San Diego Zoo Safari Park’s parking lot. Every day, the horticulturists harvest the bamboo with chain saws coated in peanut oil, which is edible, unlike grease. After harvesting, they truck it to the Zoo’s panda exhibit, where it’s put in large coolers to wait for panda mealtime.
The keepers feed the giant pandas three times per day. At each feeding the pandas are offered twice the amount of bamboo that they will actually eat. This allows the pandas to selectively “sniff test” the bamboo, as they would in the wild. The pandas spend the entire interval between feedings processing and eating bamboo.
Bamboo is a colonial organism. An entire bamboo grove behaves likes one organism, which presents challenges for the Horticulture Department. Bamboo is actually a type of grass, and it’s the fastest-growing plant on Earth. Bamboo can grow up to 98 inches (249 centimeters) in 24 hours!
Bamboo has a seasonal cycle that determines where the plant’s nutrients are stored. This cycle may drive a giant panda’s preference for the leaves or the culm, the woody central stalk of the plant. In the winter and spring, when temperate bamboo produces shoots, nutrients are stored in the culm, so giant pandas favor this protein-packed stalk. When bamboo grows new leaves in the summer and fall, photosynthesis stores sugar and protein in the leaves; therefore, the giant pandas prefer the nutrient-rich leaves.
In the wild, pandas only eat temperate bamboo, so a wild giant panda’s home range is larger in the winter, giving the panda access to more food. But zoo pandas cannot seasonally change their territories, so the keepers feed both tropical and temperate bamboo species to the pandas at the San Diego Zoo. These bamboo species have opposite reproductive cycles, so the pandas can eat leaves and culm year-round. Strangely, however, both adult giant pandas at the Zoo, Gao Gao and his mate Bai Yun, prefer to eat the hard culm year-round instead of the easily digestible leaves. Pandas are a puzzle!
Pandas aren’t the only ones that use bamboo. In the bamboo forests of China (and at the San Diego Zoo) red pandas, takins, and golden monkeys also eat bamboo. Asian cultures use bamboo for food, medicine, construction, clothing, paper, musical instruments, bicycles, and fishing rods. Bamboo is also being used as a green resource all over the world. For example, the building housing the San Diego Zoo Institute for Conservation Research is built from sustainable bamboo.
Take a shoot out of a giant panda’s book and buy environmentally friendly bamboo products. And be sure to say hello to giant pandas Gao Gao, Bai Yun, and juvenile Xiao Liwu at the San Diego Zoo or on Panda Cam.
Elise Newman is a Caravan Safari guide at the San Diego Zoo Safari Park. Read her previous post, Northern White Rhinos in Peril.